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with a gold medal, for the part which he had taken in the improvement of the Berlin Ephemeris. Our own Nautical Almanac, at that day, viz. in 1830, had fallen or had remained greatly behind the requirements of astronomers; but in speaking of the merits of the foreign Ephemeris, the report of the Council runs as follows: "A gold medal has been voted to Professor Encke for the superb Ephemeris of Berlin. It would be superfluous to dwell upon the merits of this well-known work, which, far outstripping all rivalry, must be considered as the only Ephemeris on a level with the present wants of the sciences." On presenting the medal, Sir James South, the President, adds, "With the Berlin Ephemeris, an observatory scarcely wants a single book; without it, every one." It would, however, be disloyal, though in any other aspect it may be needless, not to add that what has just been said of the Berlin Ephemeris of 1830, may with equal truth be predicated of the Nautical Almanacs from 1834 to the present date; nevertheless the first impulse came from Encke and Berlin.

Many other labors of Encke may also be found in the Memoirs and Monthly Reports of the Berlin Academy, in the As. tronomische Nachrichten, and in four volumes of the Berlin Observations. He is also well known by the publication of several excellent speeches, and especially for a memorable éloge on the celebrated Bessel.

Encke visited England in the autumn of 1840, in order to be present at the meeting of the British Association, and for the purpose of inspecting the English Observatories. His account of that journey is a testimony of the deep and pleasing impression which his hearty reception in England left upon his memory.

In 1859 Encke suffered from an apoplectic fit, and foreseeing the commencement of disease of the brain, he obtained leave of absence from his Observatory in the spring of 1863. In the autumn of the same year, finding a recurrence of the same symptoms, and knowing what they implied, with a brave heart, the now aged man explained his forebodings to a physician, and at once placed himself under his care in an institution for diseases of the brain at Kiel. At the commencment of 1864 he requested permission to be relieved from all astronomical work, and until the time of his decease, continued to live in a quiet, happy state of mind, in the midst of his family, at Spandau, near Berlin,

Encke, during the forty years of his professorship at Berlin, impressed the form and bent of his mind upon many pupils, who have ably contributed their share in the progress of astronomical knowledge. There is no greater proof of the real worth of a teacher, than when his pupils speak well and lovingly of him. They see the man in his weakness and in his strength. So it fared with Encke. They bear strong and uniform testimony to his eminent frankness and truthfulness; his labors, they say, were incessant, his recreations few; he was simple in his manners, and in all his habits temperate. Towards his coadjutors and assistants he showed a severe judgment, but he set them a severer example. A man such as this, absorbed in his work, and shutting himself away from the outer world, was likely to be sometimes abrupt, or laconic, or even incautious, in his utterances; these utterances, from their bluntness or their truthfulness, occasionally gave offense, and involved Encke in trouble. As age, however, grew upon him he became more gentle in his manners, and softer in his address; and in the presence of those whom he knew and trusted, the old man would sometimes review his own life, and urge his favorite pupils to draw from his own experience lessons of moderation and self-restraint, both in passing their judgments on the labors of others, and in the amount of labor which they felt it their duty to exact from themselves. There occurs but one more question regarding this great and venerable man; the writer of this memoir gladly adopts this language, great and venerable, because they are the very words selected by men who served him long and who knew him well, and who are themselves doing good public service in their own day. It is well known that great theological activity, not to say theological strife, surrounded Encke and every other intellectual thinker in Germany; it may not, perhaps, concern us, simply as students in Astronomy, but it cannot fail to interest us as men, to know what effect this independence of thought and boldness of expression had upon the spirit of a man, whose name will for ever be associated with some of the noblest and furthest-reaching efforts of the human mind. In reply to this question, we are told by those who knew him intimately, that Encke retained through life the strength and simplicity of his early faith; and we also learn that he was heard repeatedly to say, that one of the greatest pleasures of his life was derived from the fact, that one of his sons had become a minister of the Gospel.

C. P.

ART. III.-Sketch of the Geology of Northeastern Dakota, with a notice of a short visit to the celebrated Pipestone Quarry; by F. V. HAYDEN.

THE object of this note is simply to record some observations on the geology of Northeastern Dakota, made by me in October last, together with an account of a short visit to the celebrated Pipestone quarry. No positive inference is drawn as to the age of the rocks in which the pipestone layer is located, from the fact that no well-defined organic remains could be found. Therefore certain facts are noted down with the hope that they may hereafter aid in the solution of the problem of their age, inasmuch as their geographieal distribution seems to be quite extended.

In October last, after my return from a tour of exploration to the "Mauvaises Terres" or "Bad Lands" of White river, I took advantage of an opportunity that presented itself to visit some portions of Dakota Territory on the north side of the Missouri river not hitherto examined by me. I there made my starting point the village of Yankton, the capital of Dakota Territory, located on the Missouri, about twelve miles above the mouth of the James. At this point we observed a large exposure of the yellow calcareous marl beds of No. 3, Niobrara Division, forming along the river nearly vertical bluffs, extending sometimes several miles. The rock varies in texture from a nearly white, soft chalk, much like our chalk of commerce, to a somewhat compact limestone which is used for burning into lime and for building purposes. Thick beds of this chalk present a marked rust color from the presence of a greater or less amount of the peroxyd of iron; otherwise it could hardly be distinguished from the chalk of Europe, and without doubt would serve the same economical purposes. The organic remains found here are not very numerous in species. The most abundant shell is the Ostrea congesta Conrad, which seems to have been as gregarious and to have aggregated together much in the same way as the little oyster which is exposed when the tide recedes along the shores of the Sea Islands of South Carolina. Near the base of No. 3, there are layers of rock several feet in thickness, made up almost entirely of one or more species of Inoceramus, one of which has been identified as I. problematicus. The fish remains are quite numerous, diffused throughout the rock. Fragments, consisting of jaws, ribs and scales, are found in the greatest abundance, and Mr. Propper, a resident of Yankton has succeeded in securing some nearly perfect specimens (undescribed) from the quarries there. This group of rocks extends for four hundred miles along the Missouri river, and I am convinced that when carefully studied, it will be found to represent the White Chalk beds of Europe, and be employed for similar economical purposes.

The Cretaceous rocks of the Missouri river have been numbered in the order of superposition, Nos. 1, 2, 3, 4, 5, and all of these divisions have been located in the geological scale by the unmistakable evidence of their organic remains. We find therefore that this portion of Dakota is occupied exclusively, or nearly so, by the middle member of the Cretaceous series. The soft and yielding nature of No. 3 is well shown by the topographical features of the country, where all the slopes are gentle in their descent, and for the most part covered with a thick

growth of grass; for the soil which is composed of the eroded materials of this group is quite fertile, and in ordinary seasons produces excellent crops, and is especially adapted to the growth of cereals.

From Yankton our course was nearly north, up the west side of James river. Our path led over a gently rolling prairie for sixty-five miles, with not a tree or a bush to greet the eye. There were no cut bluffs along the little streams over which we passed; the sides of the hills bordering the valleys sloping at a very moderate angle, and being covered with a thick growth of grass. No rocks were seen in place until we arrived at Fort James, about twelve miles below the mouth of Firesteel creek, a branch of James river. Erratic rocks of all sizes and texture were visible on the surface everywhere, more especially in the valley of James river and its tributaries.

At this point on James river, uncovered by the scooping out of the valley, is a large exposure of reddish variegated quartzites, differing somewhat in structure and appearance from any rocks hitherto observed by me on the Upper Missouri. They cover a considerable area in the valley of the James at certain localities, but nowhere are they exposed at a thickness of more than twenty or thirty feet. Indeed they have been much worn by water, so that they project above the surface in large square masses, suggesting to one in the distance a village of log houses.

The rocks are mostly reddish and flesh-colored quartzites, so compact that the lines of stratification are nearly obliterated. They also appear to be metamorphic. There is, however, a horizontal as well as a vertical fracture, and the horizontal fracture breaks across what appear to be original lamine of deposition. These lines or bands are seldom horizontal; but much waved and inclined, as if the materials had been deposited in shoal or troubled waters. The illustrations of ripple or wave markings in these rocks are very numerous and beautiful. There is considerable variety in the texture of the rock; some of it is a very fine, close-grained quartzite, so that when worn by water it presents a smooth glistening surface like glass. Again it is filled with small water-worn pebbles, forming a fine pudding stone; again there are layers of siliceous sandstone, which separate into slabs varying from one fourth of an inch to several inches in thickness. This rock is very useful for building purposes, and has been employed at this point by the U. S. army officers in erecting the numerous buildings that constitute the fort. I looked diligently wherever the rock had been quarried, for some traces of organic remains, but none were visible. Resting upon the quartzite at this locality, is a bed of black plastic clay, precisely like No. 2 Cretaceous, as seen along the Missouri river near the mouth of the Vermilion. I found no fossils in this AM. JOUR. SCI.-SECOND SERIES, VOL. XLIII, No. 127. JAN., 1867.

rock, but there were numerous specimens of selenite in crystals, which characterize it in other localities. Resting on No. 2 is the Chalky marl of No. 3, not differing in structure from the same rock before described as occurring at Yankton on the Missouri river. It here contains an abundance of its characteristic fossil, Ostrea congesta. The thickness exposed is about fifty feet, but from an examination of the slope above, I estimated its entire thickness at this point at from 80 to 100 feet.

The formations at this locality, in descending order, are as follows: a. Yellow chalky marl No. 3; b. Black plastic clay with selenite crystals, undoubtedly No. 2; c. Reddish and rose-colored quartzites.

From Fort James we again proceeded across the undulating prairie, in a direction a little south of east, about 65 miles, to Fort Dakota, at Sioux Falls, on the Big Sioux river. Nothing of especial interest, in a geological point of view, met our eye except a small exposure of the reddish quartzite in the valley of Vermilion river. The soil of the prairie over which we passed, and also the superficial deposits as shown along the streams, gave unmistakable evidence that the surface features of all this region are due to the wearing away of the Cretaceous rocks Nos. 2 and 3, and that they are the immediate underlying formations. The most characteristic features which met the eye everywhere, were the boulders which cover large areas so thickly as to render cultivation impossible until they are removed. These rocks, however, will be found to be very useful to future settlers for building and other economical purposes.

At Sioux Falls there is a remarkable exhibition of the same red and variegated quartzites described at James river. They are here exposed only in the valley of the river by the removal of the superincumbent Cretaceous rocks. The falls are five or six in number, extending a distance of half a mile, and have a descent of 110 feet in all, forming the most valuable water power I have ever seen in the west. About ten feet from the top of the rocks as seen at this locality, is a layer of steatitic material, mottled, gray and cream-color, very soft, about 12 inches thick, which is used sometimes for the manufacture of pipes and other Indian ornaments. When the quartzites have been subjected to the attrition of water, they present the same smooth glassy surface as before mentioned. There are also beds of pudding stone, and the most beautiful illustrations of wave and ripple markings that I have ever observed in my geological explorations.

I was unable to discover any well defined fossils, but wherever the surfaces of the rocks had been made smooth by the attrition of water, quite distinct rounded outlines of what appeared to be bivalve shells could be seen, so numerous that the rocks must have been charged with them. The matrix is so

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